An interactive projection apparatus mainly utilizes an invisible light emitter (such as an infrared laser emitter) to generate an invisible light curtain. When an object (e.g. a stylus pen, a finger or a hand) is located within the invisible light curtain, an invisible light is reflected from the object. At this moment, the image including the reflected invisible light is photographed by a camera so as to find out the coordinate of the object. Then, the coordinate of the object is transmitted to the apparatus (PC) such that the position of the object may be acknowledged.
In some applications, more than two projectors must be utilized for forming a larger blending projection image on a projection screen. In order to obtain a seamless blending image, the projecting areas of the two projectors must be overlapped. However, if a touch point occurs within an overlap area of the projecting areas, the touch point is photographed by cameras equipped with both left and right projectors, for example. The coordinates of the same point is reported by two projection touch apparatuses. Problems of inconsistence are caused due to the different installation angles and the different ranges of two cameras of the projection touch apparatuses.
Please refer to FIG. 1, an interactive projection system 100 includes two interactive projection apparatuses U1, U2, and a computer 9 serving as an image source and a system operation control device. Each of the interactive projection apparatuses U1, U2 includes a projection unit 3, an image capture unit 4, and an invisible light emitter 2. The two projection units 3 respectively projects projection sub-images 1 onto a projection area C to form a blending image 50.
The two projection units 3 respectively projects projection sub-images 1 with an overlap area. If a touch point occurs within the overlap area, multiple time point-reporting problems occur in the interactive projection system 100 since the touch point is photographed by the image capture units 4 of both left and right interactive projection apparatuses U1, U2. In other words, different touch point positions may be obtained from different image capture units 4, which capture the touch points in near but different positions, and thus it cannot be determined which one of the different touch point positions is correct. In addition, while the projection image is blended by an operation of the user, since the installation position of the two interactive projection apparatuses U1, U2 may be different, the overlap area of the projection sub-image 1 may not be the same for each individual installation, thus it is unable to predict the position of the overlap area, and therefore the proceeding process cannot be finished.
The information disclosed in this “BACKGROUND OF THE INVENTION” section is only for enhancement understanding of the background of the invention, and therefore it may contain information that does not form the prior art that is already known to a person of ordinary skill in the art. Furthermore, the information disclosed in this “BACKGROUND OF THE INVENTION” section does not mean that one or more problems to be solved by one or more embodiments of the invention were acknowledged by a person of ordinary skill in the art.